What Is Coast FI, and How Do You Calculate It?
Coast FI is the point where your invested money will grow to your full freedom number on its own, with no further contributions. Once you hit it, you have the option to stop saving aggressively and downshift, to fewer hours, a lower-stress job, or just the room to breathe, while compounding quietly finishes the job for you.
The Straight Answer
The Day You Can Stop White-Knuckling It
When I first found FIRE (financial independence, retire early), a lightbulb went off. This was during the Great Recession, in the middle of 80-hour weeks and quarterly layoffs, so the idea that I could someday walk away felt like a far-off fantasy. Naturally, I did what every motivated 20-something does: I sprinted at a marathon. I burned out, and honestly, I’m glad that guy was so driven.
But if I’m being honest, I’d run it slower today. The sprint strained my relationships, cost me life events I didn’t have to miss, and wrapped my whole identity up in work, an identity I’d spend years afterward trying to shed.
The shift came when I stumbled onto Coast FIRE. The moment I realized that even if I never saved another dollar I was going to be okay, the weight came off my shoulders. Not rich. Not done. Just okay, guaranteed. The years I’d spent living like no one else had bought me something real: the peace of mind to speak up in a toxic room, and to walk away from it if I had to. That is what Coast FI actually buys you, long before the big number ever arrives.
What Coast FI Actually Is
Coast FI (sometimes “Coast FIRE”) is the milestone where your current invested balance, left completely alone, will compound up to your full freedom number by your target retirement age. You are not financially independent yet, you still need income to cover today’s expenses. But you no longer need to save for the future, because the future is already funded. From that point on, any job that covers your current bills is enough. The pressure to out-earn and over-save comes off. That single shift, from must-save to may-save, is the whole reason the concept matters. It’s less a wealth milestone than a permission slip.
The Formula
The Coast Point = Full Freedom Number ÷ (1 + r) ^ n
- Full Freedom Number: your annual expenses × 25 (the amount that, invested, covers you indefinitely under the 4% rule, see freedom number).
- r: an assumed real (after-inflation) annual return, for example 5%.
- n: the number of years until the age you want to be work-optional.
You have hit Coast FI when your current invested balance × (1 + r) ^ n is greater than or equal to your Full Freedom Number.
In plain terms, Coast FI just runs compound interest backward. It asks how little you’d need invested today for time alone to grow it into enough.
A Real-World Example
Say you’re 30, you want the option to stop working by 60 (30 years away), and your full freedom number is $1.8 million, the $72,000-a-year life from the freedom number walkthrough.
At a 5% real return, money grows about 4.3 times over 30 years: (1.05) to the 30th power is about 4.32.
So your Coast Point is $1,800,000 ÷ 4.32 = about $416,000.
Put $416,000 in low-cost index funds at 30, never add another dollar, and at a 5% real return it ‘coasts’ to roughly $1.8 million by 60 on its own. That $416,000 is your Coast Point. Cross it, and you’re free to earn just enough to live on, because your retirement is already handled.
The same math runs in reverse to check yourself: multiply what you have invested now by (1 + r) to the power of the years you have left. If the result clears your full number, you’ve already coasted.
The Honest Catch
Two things before you treat your Coast Point as a promise. First, that 5% is an assumption, not a guarantee. Markets don’t hand you a smooth 5% every year, they lurch, and a rough decade early on can push your real Coast Point higher than the clean formula suggests. Treat the number as a target you re-check, not a finish line you cross once and forget.
Second, coasting is not the same as quitting. Your Coast Point covers future retirement, not this month’s rent, your emergency fund, or a health surprise before Medicare. So don’t raid your runway to hit it faster, and don’t stop contributing the day you touch it if your life still feels precarious. Coast FI buys you the option to ease off, on your terms, once the rest of your foundation is solid. It doesn’t buy you the right to wing it.
Where The Coast Point Fits Your Other Numbers
If you’ve read what’s your freedom number, you already have three: your Escape Fund (the runway to walk away), your Say-No Number (enough invested to trade the toxic job for an easier one), and your Full Freedom Number (never work again).
The Coast Point is a fourth, and it changes a different thing. The Escape Fund and the Say-No Number free you from a job. The Coast Point frees you from aggressive saving. It’s often the first of the four you’ll cross, and it’s the one that quietly gives you permission to downshift years before the big number ever arrives. Same framework, one more door.
Your One Thing Tonight
Run your rough Coast Point in five minutes. Take your full freedom number (annual expenses × 25), pick a real return you believe in (5% after inflation is a reasonable, conservative starting point), and count the years to the age you’d like to be work-optional. Divide your full number by (1 + r) raised to that many years.
That figure is roughly what you’d need invested today to never save another dollar for retirement. Compare it to what you actually have. Whatever the gap, you now know the exact target that takes the white-knuckle out of saving. Grab the Freedom Number worksheet below to run all four numbers at once.
Frequently Asked Questions
What is Coast FI?
Coast FI is the point at which your existing investments will grow to your full financial-independence number on their own, with no further contributions, by your target retirement age. You still work to cover current expenses, but you no longer need to save for the future.
How do I calculate my Coast FI number?
Divide your full freedom number (annual expenses × 25) by (1 + r) raised to the number of years until your target work-optional age, where r is an assumed real return like 5%. That result is the amount you’d need invested today to coast to full independence without saving another dollar.
Is Coast FI the same as Barista FIRE?
No. Coast FI means you’ve stopped contributing and are letting your investments grow to the full number on their own. Barista FIRE means you’ve partly retired and use light or part-time work, often for the benefits, to cover current expenses while your portfolio finishes growing. Related, but not the same.
The Number That Turns Saving Into A Finish Line You Can See
Coast FI is the number that turns saving from a life sentence into a finish line you can actually see. I send a short weekly playbook on hitting these numbers faster and using them to buy back your time. Join the list below and grab the Freedom Number worksheet.
This is general information, not financial advice. The formula and figures here are an illustration to help you run your own numbers, and investment returns are never guaranteed. Talk to a qualified financial professional before making decisions about your money.
